Question: We have some 10-inch diameter water pipes running through our plant. At times, they sway up to six inches in the direction of the water flow. This is causing high maintenance requirements for the secondary lines coming off of the main line. What is causing the swaying, and how can I fix it?
Answer: I am pretty sure what you are seeing is the effect of water hammer. Water hammer (this also occurs with any fluid) is a pressure surge caused primarily by large changes in the volume of fluid being transported over a short period of time. Fugitive air that enters into water lines can also cause this.